This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-073957, filed on Mar. 18, 2002; the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a method of cleaning a deposit as formed by processing e.g. plasma etching of silicone oxide coating by using CF series gas, and a plasma processing apparatus which is cleaned by this method.
2. Description of the Related Art
There has been used frequently a plasma processing apparatus for etching a desired position of a semiconductor device, in the manufacture of the fine structure of the semiconductor device.
In such etching apparatus, a deposit as formed during the etching process in the etching chamber is frequently formed and accumulated, wherein a silicone oxide coating is etched by using an etching gas containing fluorine gas e.g. CF series compounds. Therefore, the cleaning of such deposit from the etching apparatus has to be periodically exerted.
The prior art etching apparatus for cleaning has been using a chemical cleaning with a cleaning liquid such as an organic solvent, or alternatively a physical cleaning such as water jet, air jet and the like.
As discussed above, the prior art cleaning technology for cleaning a deposit formed in a processing chamber in which a silicon oxide is etched by using CF series gas has use a chemical cleaning using a cleaning liquid such as an organic solvent, or alternatively physical cleaning using water jet or air jet.
However, among the above mentioned conventional methods of cleaning, a mere chemical cleaning step can not remove completely the deposit formed at a fine part of the member to be cleaned, such as an edge part thereof. On the other hand, a physical cleaning method such as use of water jet or air jet might impart some damage or peeling phenomenon on a deposit such as anodic oxide coating and/or a sprayed coating, when such deposit as anodic oxide coating and/or a sprayed coating are formed on the surface of the member to be cleaned.
The present invention has been attained under the consideration of such situation, and will provide a method of cleaning completely a deposit formed in the inside of a plasma processing apparatus (chamber) by processing with plasma coatings without any of damage of the deposit such as anodic oxide coating (anodized aluminium coating) and/or a sprayed coating as deposited on the surface of the member to be cleaned.
The present invention has been developed so as to solve the above mentioned problems.
In accordance with the first embodiment of the present invention, there is provided a method of cleaning a deposit formed in the inside of a plasma processing apparatus by processing with plasma coatings to be treated of a substrate by introducing a processing gas containing at least fluorine gas into the chamber, which comprises in sequence a chemical cleaning step of removing chemically the deposit by contacting a member to be cleaned having the deposit thereon with a cleaning liquid for a predetermined period, and a step of removing physically the deposit by blasting with a cleaning media the member to be cleaned, after said chemical cleaning step.
In accordance with the second embodiment of the present invention, said cleaning liquid may contain at least organic solvent.
In accordance with the third embodiment of the present invention, the organic solvent may include at least one species selected from the group consisting of ethanol, isopropyl alcohol, butanol, acetone, methyl ethyl ketone and methyl butyl ketone.
In accordance with the fourth embodiment of the present invention, the physical cleaning step is carried out by CO2 blasting step of blasting dry ice pellet with pressurized air.
In accordance with the fifth embodiment of the present invention, the pressure of air for the CO2 blasting step ranges 3.0 to 4.2 kg/cm2.
In accordance with the sixth embodiment of the present invention, the size of the dry ice pellet for the CO2 blasting step may range 0.3 mm to 0.6 mm.
In accordance with the seventh embodiment of the present invention, said physical cleaning is carried out by air jet cleaning with pressurized air and high pressure water.
In accordance with the eighth embodiment of the present invention, said air jet cleaning is carried out at water pressure of 7 to 14 MPa and air pressure of 0.2 to 0.35 MPa.
In accordance with the ninth embodiment of the present invention, an anodic oxide deposit or sprayed coating have been formed on the surface of the member to be cleaned.
In accordance with the tenth embodiment of the present invention, the method comprises further a step of exposing to air purge the member to be cleaned between the chemical step and the physical step.
In accordance with the embodiment of the present invention, the member to be cleaned is dipped in pure water after the physical cleaning step, so as to clean with supersonic vibration as generated by supersonic.
In accordance with the present invention, there is provided a method of cleaning a deposit generated by a processing gas containing fluorine gas in a plasma processing apparatus which comprises in sequence a chemical step of removing chemically the deposit by contacting a substance to be cleaned which has been deposited, with a cleaning liquid for a predetermined period; and a physical step of removing physically the deposit by blasting a cleaning media to the member to be cleaned, after said chemical step.
In accordance with the embodiment of the present invention, there is provided an apparatus for cleaning a deposit formed by treating with a processing gas containing fluorine gas into the chamber, which comprises, a chemical remover of the deposit by contacting a member to be cleaned having the deposit thereon with a cleaning processing liquid for a predetermined period, and a physical remover of the deposit by blasting a cleaning media to the member to be cleaned, after said chemical remover.